WEDNESDAY, Oct. 3 (HealthDay News) -- Children of women who suffer from high blood pressure -- or "hypertension" -- during pregnancy may pay a price even decades later, with new research suggesting these offspring score lower on thinking skills tests in old age.

Analyzing medical records from nearly 400 men born between 1934 and 1944, Finnish scientists found that those whose mothers had pregnancy-related hypertension experienced a greater decline in language skills, math reasoning and visual/spatial relationships by their seventh decade of life than men whose mothers did not have high blood pressure (the "control" group).

"We weren't surprised, given that prematurity and low birth weight are associated with lower cognitive [mental] ability, and maternal hypertensive disorders are one of the main reasons for prematurity and low birth weight," said study author Katri Raikkonen, a professor of psychology at the University of Helsinki. "I could say it would have been more surprising not to find an association. Of course, this study adds to the existing literature by showing that the effects persist into old age."

The study was published online Oct. 3 and in the Oct. 9 print issue of the journal Neurology.

According to the American Pregnancy Association, about 6 percent to 8 percent of pregnant women are affected by high blood pressure whether they had the condition prior to pregnancy or developed it during gestation.

Participants' thinking abilities were measured at age 20 and then again at an average age of 69. Raikkonen and her team found that those whose mothers had high blood pressure while pregnant scored lower at age 20 and 4.36 points lower at age 69 compared to the control group, with the decline strongest in math-related reasoning. Prematurity did not appear to affect the outcomes.

Stressing that the link between gestational hypertension and thinking skills was merely an association and not a proven cause-effect relationship, Raikkonen said several possible factors may underlie the consequences in addition to poor placental blood flow, including inflammatory responses and genetics.

But a person's environment can override any "prenatal adversities," Raikkonen noted.

"The brain continues to develop after birth and the 'window of opportunity' lays open," she said. "Though not consistently demonstrated, such postnatal environmental effects include breast-feeding and sensitive parenting."

Dr. Jennifer Wu, an obstetrician-gynecologist at Lenox Hill Hospital in New York City, said more research is needed that involves larger groups and splits participants into subsets representing different origins of pregnancy-related high blood pressure, including those with the most serious type, called preeclampsia.

"I would caution my patients that they don't need to be alarmed at this stage," Wu said. "We don't have enough information to tell them their daughter or son is going to have impaired cognitive [mental] function in 65 years. It's an interesting study, but I think there's already enough for parents to worry about in pregnancy and the first year of life."